eBay Chief Executive John Donahoe says every three months he likes to take a day-long break from running the Web retailer to map out strategy in an empty office at headquarters in San Jose, Calif. For his “thinking days” he says he eschews Powerpoint presentations in favor of an old fashioned whiteboard.

“These are pre-scheduled, uninterrupted times to step away from the chaos, zero-base my time,” says Donahoe in a posting today to LinkedIn. He says he carts around a personal priorities file with his whiteboard writings.

Indeed, despite running eBay and PayPal, Donahoe maintains a bit of an old-school style. The floor of his office is lined with stacks of printouts and overflowing manila envelopes and, until last year, he used a Motorola Razr flip phone before trading it in for an iPhone.

Donahoe says he also retreats for two weeks a year to a summer beach home in Cape Cod where he has a “rotary phone, the cell phone service stinks and the closest Internet hub is two miles away at the local library.”

“The notion that business leaders need to be connected warriors every day of the year is mistaken,” says Donahoe. “I try to completely disconnect for two weeks” every year, a process he calls “stressful.” Nonetheless, he says the experience allows him to clear his mind and to rely more on his intuition.

Donahoe’s escapes from technology echo some other tech bosses’ strategies. Bill Gates, chairman of Microsoft historically held a twice-yearly “Think Week” where he secluded himself to think big thoughts about the software maker’s future. And Sprint Nextel CEO Dan Hesse holds to only key to a private “white room” at the company’s Kansas base where he retreats to map out tactics in color-coded ink on whiteboards lining the walls.

The strategy seems to be working for Donahoe. Since taking over as CEO in March 2008, eBay shares have nearly doubled and are up 12% this year. And he is credited with turning around the company’s moribund site by improving search results, kicking off poorly-rated sellers and promoting more fixed price items, instead of auctions.